The reverse process to Ionization is recombination, in which a free electron is " captured " by a positive ion, occurs spontaneously.

Conservation of energy demands that these recombination events, in which an electron loses an amount of energy larger than the band gap, be accompanied by the emission of thermal energy ( in the form of phonons ) or radiation ( in the form of photons ).

In some states, the generation and recombination of electron – hole pairs are in equipoise.

In a direct bandgap material, recombination of these electron-hole pairs will result in cathodoluminescence ; if the sample contains an internal electric field, such as is present at a p-n junction, the SEM beam injection of carriers will cause electron beam induced current ( EBIC ) to flow.

( Lifetimes up to several milliseconds have been observed in copper ( I ) oxide ) Another limiting factor in the recombination probability is the spatial overlap of the electron and hole wavefunctions ( roughly the probability for the electron to run into the hole ).

The X-ray continuum can arise from bremsstrahlung, black-body radiation, synchrotron radiation, or what is called inverse Compton scattering of lower-energy photons by relativistic electrons, knock-on collisions of fast protons with atomic electrons, and atomic recombination, with or without additional electron transitions.

The process continues until the rate of release of new electrons in collisions is balanced by the rate of recombination of electrons with argon ions ( atoms that have lost an electron ).

The process continues until the rate of release of new electrons in collisions is balanced by the rate of recombination of electrons with argon ions ( atoms that have lost an electron ).

Pope's group reported in 1965 that in the absence of an external electric field, the electroluminescence in anthracene crystals is caused by the recombination of a thermalized electron and hole, and that the conducting level of anthracene is higher in energy than the exciton energy level.

Also in 1965, W. Helfrich and W. G. Schneider of the National Research Council in Canada produced double injection recombination electroluminescence for the first time in an anthracene single crystal using hole and electron injecting electrodes, the forerunner of modern double injection devices.

This device used a novel two-layer structure with separate hole transporting and electron transporting layers such that recombination and light emission occurred in the middle of the organic layer.

The first phase change of hydrogen in the universe was recombination, which occurred at a redshift z = 1100 ( 400, 000 years after the Big Bang ), due to the cooling of the universe to the point where the rate of combination of an electron and proton to form neutral hydrogen was higher than the ionization rate of hydrogen.

Electronic bands of O2 + ion occur in auroral spectra .. Electron-molecular-ion dissociative recombination coefficient rate α as functions of electron temperature Te and cross sections σ as a function of electron energy E have been have measured by Mehr and Biondi for N2 + and O2 + over the electron temperature interval 0. 007-10 eV.

In CMOS devices, the radiation creates electron – hole pairs in the gate insulation layers, which cause photocurrents during their recombination, and the holes trapped in the lattice defects in the insulator create a persistent gate biasing and influence the transistors ' threshold voltage, making the N-type MOSFET transistors easier and the P-type ones more difficult to switch on.

On the other hand, a deep electron trap or a site that facilitates recombination will compete for photoelectrons and therefore reduces the sensitivity.

Unlike the metals which have a continuum of electronic states, semiconductors possess a void energy region where no energy levels are available to promote recombination of an electron and hole produced by photoactivation in the solid.

The recombination of the electron and the hole must be prevented as much as possible if a photocatalyzed reaction is to be favored.

This reaction occurs quite quickly compared to the time that it takes for the injected electron to recombine with the oxidized dye molecule, preventing this recombination reaction that would effectively short-circuit the solar cell.

In the solid-state physics of semiconductors, carrier generation and recombination are processes by which mobile charge carriers ( electrons and electron holes ) are created and eliminated.

The electron – hole pair is the fundamental unit of generation and recombination, corresponding to an electron transitioning between the valence band and the conduction band.

If the centre with the hole is a luminescence centre ( radiative recombination centre ) emission of light will occur.

However, unlike n-DSCs, fast charge recombination following dye-sensitized hole injection usually resulted in low photocurrents in p-DSC and thus hampered the efficiency of the overall device.

Researchers have found that using dyes comprising a perylenemonoimid ( PMI ) as the acceptor and an oligothiophene coupled to triphenylamine as the donor greatly improve the performance of p-DSC by reducing charge recombination rate following dye-sensitized hole injection.

Carrier generation describes processes by which electrons gain energy and move from the valence band to the conduction band, producing two mobile carriers ; while recombination describes processes by which a conduction band electron loses energy and re-occupies the energy state of an electron hole in the valence band.

Unlike typical interband semiconductor lasers that emit electromagnetic radiation through the recombination of electron – hole pairs across the material band gap, QCLs are unipolar and laser emission is achieved through the use of intersubband transitions in a repeated stack of semiconductor multiple quantum well heterostructures, an idea first proposed in the paper " Possibility of amplification of electromagnetic waves in a semiconductor with a superlattice " by R. F.

( In a conventional semiconductor junction diode, the energy released from the recombination of electrons and holes is carried away as phonons, i. e., lattice vibrations, rather than as photons.

During this process, very small but finite quantities of metals remain in localized portions of the wafer: these particles of metals became deep centers of recombination, i. e. centers where current exists in a preferred way.

The spread of antibacterial resistance often occurs through vertical transmission of mutations during growth and by genetic recombination of DNA by horizontal genetic exchange.

Auger recombination is a similar Auger effect which occurs in semiconductors.

Flicker noise arises from a variety of sources, such as impurities in a conductive channel, generation and recombination noise in a transistor due to base current, and so on.

The F-plasmid is an episome ( a plasmid that can integrate itself into the bacterial chromosome by homologous recombination ) with a length of about 100 kb.

The transferred DNA can then be integrated into the recipient genome via homologous recombination.

The cosmic microwave background is radiation left over from decoupling after the epoch of recombination when neutral atoms first formed.

Chromosomal recombination plays a vital role in genetic diversity.

This is usually done by sophisticated recombination of musical phrases extracted from existing music, either live or pre-recorded.

In live performance, the system re-injects the musician's material in several different ways, allowing a semantics-level representation of the session and a smart recombination and transformation of this material in real-time.

Cosmologists refer to the time period when neutral atoms first formed as the recombination epoch, and the event shortly after of photons starting to travel freely through space rather than constantly scattering with electrons and protons in plasma is referred to as photon decoupling.

* termination ( elementary step in which active particle loses its activity without transferring the chain ; e. g. recombination of the free radicals ).

: As a dopant, gold ( or platinum ) acts as recombination centers, which helps a fast recombination of minority carriers.

It is also required for V ( D ) J recombination, the process that generates diversity in immunoglobulin and T-cell receptor loci during immune system development.

One vital aspect to performing efficient recombination experiments involving the ligation of cohesive-ended fragments is controlling the optimal temperature.

They can be hybrids produced through crossover ( a form of genetic recombination ) of chromosomes, which takes place in meiosis.

This mutation, recombination, and the fact that the two chromosome sets ultimately come from either a grandmother or a grandfather on each parental side account for the genetic dissimilarity of siblings.

About 300, 000 years after this event, atoms of hydrogen and helium began to form, in an event called recombination.

# Evolution is gradual: small genetic changes, recombination ordered by natural selection.

This causes the emission of a photon carrying away the energy produced upon recombination.

As gas density increases at lower altitudes, the recombination process prevails, since the gas molecules and ions are closer together.

The vertical structure of the E layer is primarily determined by the competing effects of ionization and recombination.

Gam and red proteins are involved in recombination.